Grinding wheel dressing mechanism



S. P. BRUCE GRINDING WHEEL. DRESSING MECHANISM March 3, 1953 2SHEETS-SHEET 1 Filed Feb. 5, 1949 March 3, 1953 s. P. BRUCE GRINDINGWHEEL DRESSING MECHANISM 2 SHEETS-SHEET 2 Filed Feb. 5, 1949 PatentedMar. 3, 1953 GRINDING WHEEL DRESSING MECHANISM Stanford P. Bruce,Detroit, Mich., assignor to Wheel Trueing Tool Company, Detroit, Mich.,a corporation of Delaware Application February 5, 1949, Serial No.74,775

4 Claims.

1 The present invention relates to a grinding Wheel dressing assemblywherein dressing tools,

particularly diamond tools, are used to true or dress the surface of anabrasive wheel.

As abrasive wheels become worn or otherwise out of true from prolongeduse, it is customary practice to dress or true the cutting surface ofthe wheel by passing a'cutting tool, such as a diamond point, across thesurface thereof parallel to the axis of rotation of the Wheel, to dressor reshape the wheel to its proper configuration.

Continued use of a diamond dressing tool tends to wear the diamond pointunevenly, resulting in Worn surfaces, or flats being formed on thediamond, a condition which impairs its usefulness. To overcome thisobjection, in my previously filed application Serial No. 744,749entitled Grinding Wheel Dressing Mechanism, filed April 29, 1947, nowPatent No. 2,597,616, dated May 20, 1952, I have described a rotatabletool holder for mounting diamond dressing tools. This tool holder iscapable of imparting intermittent step by step rotation to the diamondtool, so that all faces of the diamond tool are worn evenly, and thediamond ultimately acquires a generally pyramidical configuration ofcutting surfaces. While this improvement has been eminently successfulin prolonging the useful life of diamond tools, difliculties have arisenin mounting the tool in certain grinding wheel installations due to thelimited amount of space available for mounting the dressing assembly andits adjuncts.

This invention relates to an improvement in grinding wheel dressingassemblies providing a mounting for indexing dressing tools from remotepositions.

An object of the present invention is to provide a grinding wheeldressing assembly containing a rotatable tool holder which may beautomatically rotated by means of a remote indexing become apparent fromthe following description and the discussion of the attached drawings.

In general, this invention provides a grinding wheel dressing assemblycontaining a rotatable dressing tool mounted in a conventional slideassembly for traversing movement across the surface of a grinding wheel,and remote actuating 2 means for imparting rotating movement to thedressing tool at the completion of the traversing movement across thesurface of the grinding wheel.

A more complete description of the present invention will be made inconnection with the attacned drawings, in which:

Figure 1 is a fragmentary perspective view of the dressing assembly ofthe present invention mounted on a conventional Cincinnati centeriesstype grinding machine;

Figure 2 is a mom; elevational view of the gear box housing therotatable diamond tool holder and the driving gear, with the coverremoved;

Figure 3 is a cross-sectional View taken along line IIl-III of Figure 2,with parts inelevation;

Figure 4 is a longitudinal vertical sectional View of the remoteindexing mechanism; and

Figure 5 IS a cross-sectional View taken along the line VV of Figure 1.

As shown on the drawings:

Reference numeral la denotes in general a grinder of the Cincinnaticenterless type having an abrasive wheel II and a guard i2 spaced fromand surrounding the periphery of the grinding wheel Ii. Pro ectingthrough the guard l2 and slidably mounted therein is a conventionalslide i3 containing a rotatable tool holder l4 and a 'diamondtool 5. Theslide I3 is mounted for sliding movement in a direction parallel to theaxis of the grinding wheel II. 'A gear box [6 hereinafter described.

The slide 13 is housed in a carriage l'l. for sliding movement along atable 18 which has a stop l9 mounted at ortnear one end. The carriage llcarries aratchet wheel housing 26 containing a movable pin 2| projectingtherefrom. A flexible cable 22 is also secured to the ratchet wheelhousing 20 by means of a coupling 23. The other end of the flexiblecable 22 passes through the guard 12 and terminates in the gear box i6.Attached to the stop I9 is a bracket 25 (Fig. l) which serves to contactthe slidable pin 2| projecting from the ratchet housing 20 when theslide assembly has reached its farthermost limit of travel along thetable 68. When the bracket 24 is contacted by the sliding pin 2 I, thepin 21 actuates a ratchet mechanism contained in the ratchet housing 20to rotate the same, the rotative movement of the ratchet beingtransmitted via the flexible cable 22 to the driving gear contained ingear box [6 which, in turn, imparts a step-by-step rotation to therotatable tool holder 14 and the corresponding diamond point 15. Theassembly is so arranged that the slidable pin 2| contacts the bracket 24after the diamond tool l has completed its traverse across the face ofthe grinding wheel II and is out of contact with the grinding wheel I I.At such time the tool holder I4 is rotated to present a new cutting faceto the surface of thegrinding wheel I I.

The assembly shown in Figure 1 also includes pressure lines 25, apressure gauge 26 and electric power lines 21. u

The gear housing 16, as best'shown in Figures 2 and 3, consists of agenerally eliptical-"member 28 and a cover plate 29, the latter beingsecured to the member 28 by means of screws 30. The member 28 isprovided with a cylindrical shaft 3| adapted to be mounted securelywithin the slide l3. Formed within the shaft 3| 'is-an internal recess32 which receives the pilot 33 of the tool holder [4.

The tool holder l4=is provided with an annular flange 34 and with asprocket gear 35 having teeth 38. The tool holder [4 is also providedwith-aninternal bore 3! for the reception of the diamond tool IS. Thediamond tool I5 is secured within the tool holder [4 by a set screwthreaded into :an aperture 38 in the tool holder =14. A washer 39 isdisposed about the flange portion 34 of the toolholder 1-4.

The sprocket gear 35 is meshed with a similar driving sprocket gear 40having teeth 42, which is disposed against the innersurface of member28-andspaeed from the cover plate 29 by means of a spacer 41. Thisdriving gear 40-contains a hub 60 rotatably mounted in a recess 46 ofthe cover plate 29. The driving gear40 is actuated by attaching it tothe inner flexible shaft 43 of the flexible cable 22, which includes asheath 44 and a coupling 45. The coupling 45 is held in member 28 as bymeans of welded joints.

As best shown in Figures 4 and 5, the ratchet housing '20 consists of abase member 41 and a 'vertical housing 48 rigidly attached thereto.

'Thebase 4'1o'f'the ratchet housing 28 is formed into -a channel 49 forslidably containing a slide member "50. Secured to the slide 50 andmovable therewith is the pin 2| which projects throughan aperture 5l ina flange 52 projecting from the base 41, "The slide 50 carries a pawlmember '53 for actuating a ratchet wheel 54 secured to the inner shaft43 of the flexible cable 22. A hub 6| of the ratchet wheel 54 isrotatalbly mounted within a recess 62 provided in the housing 48. Thepawl 53 is pivotally mounted d to the slide 50'by means of a pin 55, andis held in upright position by means of a spring 55 which urges "the"pawl '53 against an upstanding 'fla'ngeportion '51'of 'th'e'slide5tl.The slide '50 is also provided with "a recess 58 to give added freedomof pivotal movement of the pawl 53 around the pin 55. j I

The slide'50isnormallyh'eld'in a'po'sition such thatthepawl 53 is out ofcontact with the ratchet wheel'54 by means of 'a spring 58 actingbetween the flange portion52 and the slide 50.

The operation of the apparatus is as follows:

When the diamond tool I 5 has made a traverse of the grinding wheel 11and is out of contact therewith, the sliding pin 2| contacts theupstanding bracket '24, causing the pin 2! and the slide 5b to move inthe channel 49 against t e action of the s ring 59. The aw] 3 th s cntacts a tooth of the ratchet wheel F4 an rotates the ratchet wheel 54through an angular distance represented by the spacing betweensuccausing thetool holde'r assemb'ly and the diar'no'nd tool *I 5-contained therein torota-te through a corresponding small arc.

As the carriage I! is moved in the opposite direction for another passacross the surface of the abrasive wheel, "the spring 59 urges the slide'53 back into "its normal position. The pawl 53 "slips under thelowermost tooth of the ratchet wheel-'54'by-virtue of its being pivotedat pin 55.

This arrangement permits the pawl 53 to pass under the teeth of theratchet wheel 54 without inadvertently rotating the ratchet wheel in thewrong direction. After the pawl 53 has passed out of contact with theteeth of the ratchet wheel .54, it is restored to its normal upstandingposition against'the flange portion-57 of 'the slide 58 by means of theaction of the spring 56. The assembly is then in position for anothertraverse across "the face of the-grinding wheel.

From theforegoing it -wi1'1-be apparent thatI have herein provided agrinding wheel dressing assembly utilizing a rotatable tool holder andhave "provided means -'for periodically rotating the tool "holder from aremote posi tion. it will be appreciated that the presently describedapparatus is especially adapted for mounting in grinding wheelmechanisms wherein a limited amount of space is provided, or where thediamond tool is inaccessible for purposes of rotating v the same afterthe traverse across the grinding wheel.

it will ''be apparent 'that many modifications may be made to theapparatus as herein described, and it is not-my-intention to limit theinvention described herein other thanas ne'cessitated by the scope ofthe appended claims.

-I claim as 7 my invention: -1. A mechanism for automatically indexing-a dressing tool at an end of it's traverse over the face of a grindingwheel in an assembly including a 'bed, a carriage =m0veable 'over saidhad, a tool holder mounted on said carriage and r0- tatable about itsown axis, and a=g rinding wheel traversed by saidcarriage in itsmovementpsaid tool holder carrying a dressing tool which engages theperipher-y of saidgrinding WheePdur-irig, said traverse, said mechanismcomprising a "first means coupled to said tool holder to rotate thesame, arotatable-member mounted-on said can riage remote from said firstmeans, torque transmitting means connecting said rotatable mernber andsaid first means, a second means including a reciprocating pawl forrotating said rotatable member and a stop positioned on-saidbedbeyondthe end of the traverse of said 'carriageand arranged to be contactedby-said reciprocating awl and acting through said rotatable member, saidtorque transmitting means and said first means to rotate said toolholder.

2. A mechanism for automatically indexing a dressing tool at an end ofits traverse over the face of a grinding wheel in an assembly includinga bed, a carria e moveable over said bed, :a tool holder mounted on aidcarriage and rotatable about its own axis, and a grinding wheeltra'ersetl by said carriage in its movement said tool holder carryinga'dressing tool which engages the periphery of said grinding wheelduring said traverse, said mechanism comprising a first means coupled tosaid tool holder to rotate the same, a rotatable member mounted on saidcarriage remote from said first means, a flexible cable means connectingsaid rotatable member and said first means, a second means including areciprocating pawl for rotating said rotatable member and a stoppositioned on said bed beyond the end of the traverse of said carriageand arranged to be contacted by said reciprocating pawl and actingthrough said rotatable member, said flexible cable means and said firstmeans to rotate said tool holder.

3. A mechanism for automatically indexing a dressing tool at an end ofits traverse over the face of a grinding wheel in an assembly includinga bed, a carriage moveable over said bed, a tool holder mounted on saidcarriage and rotatable about its own axis, and a grinding wheeltraversed 'by said carriage in its movement, said tool holder carrying adressing tool which engages the periphery of said grinding wheel duringsaid traverse, said mechanism comprising a first means coupled to saidtool holder to rotate the same, a ratchet wheel mounted on said carriageremote from said first means, a flexible cable means connecting saidratchet wheel and said first means, a second means including areciprocating pawl for rotating said ratchet wheel and a stop positionedon said bed beyond the end of the traverse of said carriage and arrangedto be contacted by said reciprocating pawl and acting through saidratchet wheel, said flexible cable means and said first means to rotatesaid tool holder.

4. A mechanism for automatically indexing a dressing tool at an end ofits traverse over the face of a grinding wheel in an assembly includinga bed, a carriage moveable over said bed, a tool holder mounted on saidcarriage and rotatable about its own axis, and a grinding wheeltraversed by said carriage in its movement, said tool holder carrying adressing tool which engages the periphery of said grinding wheel duringsaid traverse, said mechanism comprising a gear train coupled to saidtool holder to rotate the same, a ratchet wheel mounted on said carriageremote from said gear train, a flexible cable means connecting saidratchet wheel and said gear train, means including a reciprocating pawlfor rotating said ratchet wheel and a stop positioned on said bed beyondthe end of the traverse of said carriage and arranged to be contacted bysaid reciprocating pawl and acting through said ratchet wheel, saidflexible cable means and said gear train to rotate said tool holder.

STANFORD P. BRUCE.

REFERENCES CITED The following references are of record in the file ofthis patent:

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